So, when will software RAID hotswap work? Or, is it just one of those things that is just infeasible?

We'd like to use this for our lower-end boxes (1U, 4 hard drive), so we don't have to waste money or slots with a raid controller. At this low end, software raid and hardware raid are pretty close in performance (not counting controller cache), and one of the boxes we use has a special connector that hooks up from the hot-swap back-plane to the motherboard, so it'd be kind of a pain to have to get another kind of cable to hook up to a hardware raid controller.